Who takes a domain’s mail

Reads the MX records a domain publishes and says which mail provider they name, so an owner connecting a company mailbox is not asked for server details their own DNS already answers.

Only records that name a provider settle anything. A domain whose mail goes to a filter first is reported as filtered with no provider, because the filter says who scans the mail and not who holds it, and offering the wrong provider hands somebody a sign-in screen for a service they do not use. A domain that publishes no MX records at all comes back with an empty list, which is an answer; a lookup no resolver would answer comes back unreachable, which is not.

The lookup is DNS, so the answer is public information about the domain and carries nothing about the account asking.